Controversial plans to build a 13-room basement under a landmark Grade II listed house immortalised by painter John Constable have been given the green light by planners.

The scheme caused an outcry among conservationists and divided neighbours.

Grove House, which adjoins the grand neighbouring Admirals House, in Admirals Walk and dates back to 1700 was home to novelist John Galsworthy from 1918 to 1933. He penned his famous Forsyte saga there.

It has been painted by Constable three times and scenes from the Mary Poppins movie with Dick van Dyke

were also filmed in the associated Admirals House.

Grove House’s new owners, city financier Caspar Berendsen and wife Celia applied for permission to

demolish part of the building, once a service wing to Admirals House, and replace it with a new two storey side extension and rear extension, orangery and outbuilding and to dig a huge 13-room basement.

The plans, from NA architects, aim to “provide a more comfortable living environment for the applicant and his

large and young family” and “to deliver a 21st century family home”.

It is claimed the scheme will “bring the historic main building closer to the original design” with most of the extension hidden underground.

But John Gardiner, who has lived in adjoining Admirals House for 28 years and who addressed planners last night, said: “This would be a disastrous destruction of Hampstead’s, and indeed London’s, historic heritage.”

He said: “The sheer scale of the development creates a new mansion destroying the characteristics

that presently remain of an early farmhouse.”

He also points out that, along with building works to nearby Fleet House, the area will see months of heavy construction.

Actor Tom Conti, had also objected to the plans. He said: “I’m radically opposed to basements on the grounds of inhumanity to those in the area of construction.”

Hundreds of protesters have signed a petition against the plans

However Camden planners voted in favour of the scheme after hearing from Mr Berendsen that he had revised the scheme several times to take neighbours concerns into account.